Portion of an internal combustion engine



FIG. 1 is a front perspective view of a portion of an internal combustion engine showing our new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a plan view thereof;

FIG. 6 is a bottom view thereof;

FIG. 7 is a left side view thereof; and,

FIG. 8 is a right side view thereof.

The broken lines in FIGS. 1-8 illustrate portions of the engine that form no part of the claimed design. 

The ornamental design for a portion of an internal combustion engine, as shown and described. 